The trailer hints at troubled moments ahead for the rookie lecturer.

Drinking Solo, also known as Drinking Alone or Let's Drink, returns on tvN with its sixth episode tonight, Sept. 20, at 11pm KST. The sequel will revolve around the challenges faced by rookie lecturer Park Ha na.

Episode 6 of the South Korean period drama will also focus on the various efforts put forward by Jin Gong myung to impress his teacher. So, the viewers can expect a love triangle between Park Ha sun's character, her colleague Jin Jung-suk and her student.

Watch Drinking Solo episode 6 live online here to find out what is next in store for Ha na, Jung Suk and Gong myung in the show.

Meanwhile, tvN has released an official trailer of the upcoming episode through its You Tube channel. The 30-second-long promo begins with a scene between Ha sun's character and her student, wherein the two are seen spending quality time with each other.

Gradually, the teaser opens up to a tense sequence and it shows the female lead trying to make her student understand that a romantic relationship between them is not possible. However, Gong myung does not seem to be moved by her words as he is seen putting her head on his shoulder and smiling.

The sneak peek video then takes its viewers to Noryangjin Institute and focuses on Ha na, who seems a bit nervous after seeing a class full of students. Although she tries her best to act normal, she faints in front of her students. The clip ends with a scene between director Kim Won-hae and Jung suk.

The upcoming sixth episode of Drinking Solo will also feature Shinee member Key as Kim Ki bum, Jung Chae yeon and Kim Dong-young as ninth grade civil service students of Noryangjin Institute as well as Min Jin woong as their teacher.